What is the central religious text of Zoroastrianism?

The central religious text of Zoroastrianism is the Avesta. It is a collection of sacred writings in Avestan, an ancient Iranian language, rather than a single book written at one time.

The Avesta was assembled over many centuries, and much of the original material was probably lost. Its most important sections include the Yasna, used in ritual worship; the Gathas, hymns traditionally attributed to Zoroaster; the Visperad, which expands the liturgy; and the Vendidad, a text containing religious laws, purity rules, and mythic material. The Khordeh Avesta is a later prayer collection widely used in daily devotion.

A common mix-up is treating the Yasna or Gathas as the entire scripture. They are major parts of the Avesta, but neither name refers to the complete body of Zoroastrian sacred texts. Zoroastrian tradition also places strong emphasis on oral transmission, which helped preserve teachings before and alongside written compilation. The Avesta remains central to Zoroastrian worship, ethics, prayer, and understanding of the teachings associated with Zarathushtra, better known in Greek as Zoroaster.